Hydraulic jack.



No. 848,641. PATEN TED APR. 2, 1907.

H. G. DUDGEON. 7

HYDRAULIC JACK.

APPLICATION FILE-D MAY 2,1906.

i/bvieaoep i avvua'mm UNITED STATES PATENT OFFICE.

HYDRAULIC JACK.

Specification of Letters Patent.

Patented April 2, 1907.

Application filed MayI2,-1906. Serial lilo- 314,841.

To a whom it may concern:

Be it known that I, HENRY C. DUDGEON, a citizen of the United States, and a resident of Locust Valley, Nassau county, Long Island, State of New York, have invented a new and useful Improvement in-Hydraulic Jacks, of which the following is a specification, reference being had to theaccompanying draw' mg, whlch illustrates a vertical sectional view of the head of a jack embodying the invention, certain parts being shown in elevation.

In the drawing I show the invention as applied to a common form of hydraulic ack that is to say, one in which the head of the jack is made hollow, so as to contain the liquid, and I have shown it as mounted directly upon the upper end of the ram.

In apparatus of the class stated it is essen' tial that the receptacle which contains the necessarily-present liquid shall be provided with an air-vent, so that as the liquid is pumped from this receptacle into the forc'e chamber air entrance may be afforded to break the vacuum which would otherwise be formed and likewise so that air may be ejected from the receptacle upon the return of the liquid thereto when it-is desired (as it is called) to lower the jack As heretofore constructed the air-vent has been of such character that it was permanently open, thus permitting entrance and exit of the air at all times, and consequently, also, permitting constant vaporization of the liquid which is usually quite volatile or its outflowing in the event that the jack becomes upset or left in any position other than that in which the liquid would remain in the receptacle under the action of gravity, and since hydraulic jacks are frequently subjected to very rough treatment in the hands of a class of workmen the jack. B" B are two of the lugs usually cast on its upper surface. C is the ram of the jack. D is the pump-knuckle; E, the shaft of the knuckle. Fis thepiston-rod. G is the crank-pin on which the piston-rod rocks. All these parts may be of any usual construction.

riphery, as shown at I I, into a suitable recess made in the head of the jack. I prefer vto provide shoulders J J at or near the lower end against which the block may be screwed down tight.

K K are two threaded recesses made in the block H, one opening at its upper, the other at its lower, end.

L L are two bonnets which are screwed into the threaded recesses K K and are each provided with air-inlet openings M M, respectively, and there may be as many of these openings as preferred.

V N N are two passage-ways made through the block H, connecting with the recesses K K, respectively. The passage-way N opens inwardly intothe head of the jack, and the passage-way N outwardly into the open air.

with spindles, as shown, and P P are the springs which normally reseat these valves upon their respective seats in the passageways N N, as shown. I v

Q may be assumed to be the level of the 'liquid in the head of the jack.

The operation is simple. Upon working the pum the liquid is drawn from the cavity within t e head A, passed down through the iston of the pump and by it forced into the orce-chamber beneath the ram in the ordiamount of the li uid has thus been removed from the head t e tendency to produce a vacuum therein arises. When the pressure resiliency of the spring P, the valve 0 will be forced off its seat by atmospheric pressure, and air will enter through the valve 0, passing inwardly through the opening N into the head, thus relievin the vacuum. In this cavity within the head from'time to time, as

therefrom, .and also that at all times, excepting the periodical moments when the valve is opened for the admission of the air, the s ring P will maintain the valve 0 closed. ikewise after the ram has done its work and it is desired to lower the head, which may be effected in the ordinary way, the li uid will flow back again into the cavity in t e head, thus tending to produce air-compression H is a block of metal threaded on its peincident thereto is sufficient to overcome the way it will be seen t at air is supplied to the required, by the subsidence of the liquid O O are two checkvalves, each provided nary' way. As soon as any considerable therein, and as soon as the pressure equals that of the spring P the valve 0 will be lifted from its seat, permitting the air to escape through the passages N and M. As soon as the incoming of the liquid ceases-in other words, after the head has been lowered to the desired extentthe valve 0 will be automatically seated again by the spring P. In this way, it will be noted, by my invention I avoid the necessity for any manual act what-. ever.

The devices automatically perform their work without intervention of any kind by the operator and without the exercise of any care, thoughtfulness, or intelligence by him, and that at all times, excepting tlfe periodical moments when the valves are automatically opened, they remain closed, so that there is no opportunity for loss of liquid by vaporization or outflowing from the cavity in which it is contained] It will be noted that under my invention the oppositely-acting spring-controlled valves are located within the Wall of the reservoirin other words, the head of the ackand that they are bodily inclosed therein, free from distortion or disarrangement incident to the -exceedingly rough usuage that hydraulic 'j'ack's are subjected to, and that by'the construction shown I solve a problem in the manufacture of hydraulic jacks, never heretofore adequately solyed, so far as I am aware, in a most simple, durable, and eflective manner.

I claim ,7 1. In an hydraulic jack, the combination of a reservoir in the head of the jack from which the pump receives its supply of liquid,

automatically-acting valves set within thewall ofthe reservoir without projection beyond its outer surface and which operate in reverse directions, connecting the interior of the reservoir with the external air.

2. In an hydraulic ack, the combination of a reservoir in the head of the jack from which the pump receives its supply of liquid, two valves set in the wall of the reservoir without projection beyond its outer surface, each having a reseating-spring, one adapted to be opened by pressure from within the reservoir outwardly, and the other by pressure from without the reservoir inwardly.

3. In an hydraulic jack, the combination of a reservoir in the head of the jack from which the pump receives its supply of liquid, a block threaded vinto the wall of the reservoir, the exterior surface whereof is flush with the exterior surface of the reservoir, openings through said block, valves seated therein art of which project beyond the outer sur ace of the block, one adapted to beopened by pressure from within the reservoir outwardly and the other by pressure from Without the reservoir inwardly and springs which normally reseat said valves.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HENRY o. DUDGEON.

Witnesses:

F. M. DRUSBACH, PHILLIPs ABBOTT. 

